The Effect of Water Ingress on the Thickener Structure in Bio-based Greases"
This paper by Johanna Larsson and Roland Ardai of AXEL Christiernsson presents how different oil and thickener combinations respond to water and how this affects grease performance as lubricants at both normal operating conditions and at low temperatures.
Environmentally adapted greases are coming into contact with water in most applications where they are used. Even when they are contaminated with water these greases are expected to provide lubrication, protect component surfaces and keep contaminants out of bearings while maintaining their rheological properties. Additionally, in the event of release into the environment, these greases need to decompose without any, or at least minimal, impact. Previous studies performed by the authors evaluating different types of bio-greases contaminated with water have shown superior performance of anhydrous calcium greases. The ability of a grease to keep its technical performance after water ingress is related to how water interacts with and affects the thickener structure.